Solid-Phase Three-Component Domino Reactions: Combinatorial Approach to Substituted 3,4-Dihydro-2<i>H</i>-pyrans

Abstract

Resin-linked acetoacetate 1 reacts with aldehydes 2 to give the Knoevenagel products 3, which undergo hetero-Diels-Alder-reactions with the enol ethers 4 to afford the polymer-bound cycloadducts 5/6. Cleavage from the support is achieved by base-induced transesterification to give the 3,4-dihydropyrans 7/8 in high purity. The suitability of these transformations for generating combinatorial libraries is demonstrated.